C-arm fluoroscopy machines are often used in hospital emergency rooms and trauma centers. These machines have an arm which supports an x-ray source spaced apart from an x-ray detector. The arm can be manipulated to place the x-ray source on one side of a patient and the x-ray detector on the other side of the patient. A series of joints permits the arm to be moved to a pose which will provide a desired x-ray image. A monitor displays the x-ray image in real time.
C-arm fluoroscopy machines may, for example, be used to image the locations at which pins or screws will be inserted to hold broken bones in place.
One issue with the use of C-arm fluoroscopy machines is limiting the amount of x-rays to which physicians and other medical personnel are exposed. In many procedures a physician's hands will be in the field irradiated by x-rays. Although modern x-ray machines can acquire acceptable images with a lower dose than was formerly possible there is a limit to the dose reduction that can be achieved by this route.
Another approach to reducing x-ray exposure to medical personnel is reducing the amount of time required to obtain desired images. Providing a mechanism to track the position of an x-ray source and detector can help to reduce the time taken to obtain desired images. A tracking system may also facilitate a range of useful functionalities that are based on known spatial positions of radiographs relative to one another and to a patient.
Optical localizers have been proposed for tracking the position of the arms of C-arm fluoroscopy machines. Such localizers use cameras to track the positions of targets mounted on the C-arm. Optical trackers have a number of deficiencies. For example, the camera requires an unobstructed line of sight to the targets. This constrains the use of valuable operating room space. This problem is made worse because a C-arm is relatively large and must be able to be moved through a large range of motion. Thus maintaining an unobstructed line of sight between camera and targets places serious constraints on the positioning of other operating room equipment and operating room personnel. In addition, optical localizers can have high costs.
The following references describe technology in the general field of the present invention:    Cho Y, Moseley Dj, Siewerdsen Jh, Jaffray Da (2005) Accurate Technique For Complete Geometric Calibration Of Cone-Beam Computed Tomography Systems. Medical Physics 32 (4):968-983    Daly Mj, Siewerdsen Jh, Cho Yb, Jaffray Da, Irish Jc (2008) Geometric Calibration Of A Mobile C-Arm For Intraoperative Cone-Beam Ct. Medical Physics 35 (5):2124-2136    Binder, Norbert, Christoph Bodensteiner, Lars Matthaus, Rainer Burgkart, and Achim Schweikard. The Surgeon's Third Hand an Interactive Robotic C-Arm Fluoroscope. Mobile Robotics—Moving Intelligence (2007): 403-418.    Binder, Norbert, Lars Matthaus, Rainer Burgkart, and Achim Schweikard. A robotic C-arm fluoroscope. The International Journal of Medical Robotics and Computer Assisted Surgery 1, no. 3 (2005): 108-116.    Jain, Ameet, and Gabor Fichtinger. C-arm tracking and reconstruction without an external tracker. In Medical Image Computing and Computer-Assisted Intervention—MICCAI 2006, pp. 494-502. Springer Berlin Heidelberg, 2006.    Matthäus, Lars, Norbert Binder, Christoph Bodensteiner, and Achim Schweikard. Closed-form inverse kinematic solution for fluoroscopic C-arms. Advanced Robotics 21, no. 8 (2007): 869-886.    Matthews, Felix, Dominik J. Hoigne, Manfred Weiser, Guido A. Wanner, Pietro Regazzoni, Norbert Suhm, and Peter Messmer. Navigating the fluoroscope's C-arm back into position: an accurate and practicable solution to cut radiation and optimize intraoperative workflow. Journal of orthopaedic trauma 21, no. 10 (2007): 687-692.    Navab, Nassir, Stefan Wiesner, Selim Benhimane, Ekkehard Euler, and Sandro Michael Heining. Visual servoing for intraoperative positioning and repositioning of mobile C-arms. In Medical Image Computing and Computer-Assisted Intervention—MICCAI 2006, pp. 551-560. Springer Berlin Heidelberg, 2006.    Wang, Lejing, Rui Zou, Simon Weidert, Juergen Landes, Ekkehard Euler, Darius Burschka, and Nassir Navab. Closed-form inverse kinematics for intra-operative mobile C-arm positioning with six degrees of freedom. In SPIE, vol. 7964, no. 1, p. 79641A. 2011.    Wang, Lejing, Pascal Fallavollita, Rui Zou, Xin Chen, Simon Weidert, and Nassir Navab. Closed-form inverse kinematics for interventional C-arm X-ray imaging with six degrees of freedom: modeling and application. Medical Imaging, IEEE Transactions on 31, no. 5 (2012): 1086-1099.    Hofstetter R, Slomczykowski M, Sati M, Nolte Lp (1999) Fluoroscopy As An Imaging Means For Computer-Assisted Surgical Navigation. Computer Aided Surgery 4 (2):65-76    Hofstetter R, Slomczykowski M, Krettek C, Koppen G, Sati M, Nolte Lp (2000) Computer-Assisted Fluoroscopy-Based Reduction Of Femoral Fractures And Antetorsion Correction. Computer Aided Surgery: Official Journal Of The International Society For Computer Aided Surgery 5 (5):311-325. Doi:10.1002/1097-0150(2000)5:5<311::Aid-Igs1>3.0.Co; 2-J    Foley Kt, Simon Da, Rampersaud Yr (2001) Virtual Fluoroscopy: Computer-Assisted Fluoroscopic Navigation. Spine 26 (4):347-351    Chen X, Wang L, Fallavollita P, Navab N (2013) Precise X-Ray And Video Overlay For Augmented Reality Fluoroscopy. International Journal Of Computer Assisted Radiology And Surgery 8 (1):29-38. Doi:10.1007/S11548-012-0746-X    Binder N, Matthaus L, Burgkart R, Schweikard A (2005) A Robotic C-Arm Fluoroscope. The International Journal Of Medical Robotics+Computer Assisted Surgery: Mrcas 1 (3):108-116. Doi:10.1002/Rcs.34    Reaungamornrat S, Otake Y, Uneri A, Schafer S, Mirota Dj, Nithiananthan S, Stayman Jw, Kleinszig G, Khanna Aj, Taylor Rh, Siewerdsen Jh (2012) An On-Board Surgical Tracking And Video Augmentation System For C-Arm Image Guidance. International Journal Of Computer Assisted Radiology And Surgery 7 (5):647-665. Doi:10.1007/S11548-012-0682-9    Reaungamornrat S, Otake Y, Uneri A, Schafer S, Stayman J, Zbijewski W, Mirota D, Yoo J, Nithiananthan S, Khanna A (2011) Tracker-On-C: A Novel Tracker Configuration For Image-Guided Therapy Using A Mobile C-Arm. Computer Assisted Radiology And Surgery, Berlin, Germany:22-25    Bo Le, Leira Ho, Tangen Ga, Hofstad Ef, Amundsen T, Lango T (2012) Accuracy Of Electromagnetic Tracking With A Prototype Field Generator In An Interventional Or Setting. Medical Physics 39 (1):399-406. Doi:10.1118/1.3666768    Hummel J, Figl M, Birkfellner W, Bax Mr, Shahidi R, Maurer Cr, Jr., Bergmann H (2006) Evaluation Of A New Electromagnetic Tracking System Using A Standardized Assessment Protocol. Physics In Medicine And Biology 51 (10):N205-210. Doi:10.1088/0031-9155/51/10/N01    Grzeda V, Fichtinger G (2010) C-Arm Rotation Encoding With Accelerometers. International Journal Of Computer Assisted Radiology And Surgery 5 (4):385-391. Doi:Doi 10.1007/S11548-010-0415-X    Grzeda V, Fichtinger G (2010) Rotational Encoding Of C-Arm Fluoroscope With Tilt Sensing Accelerometer. Lect Notes Comput Sc 6363:424-431    Livyatan H, Yaniv Z, Joskowicz L (2002) Robust Automatic C-Arm Calibration For Fluoroscopy-Based Navigation: A Practical Approach. In: Dohi T, Kikinis R (Eds) Medical Image Computing And Computer-Assisted Intervention—Miccai 2002, Vol 2489. Lecture Notes In Computer Science. Springer Berlin Heidelberg, Pp 60-68. Doi:10.1007/3-540-45787-9_8    Burkhardt D, Jain A, Fichtinger G (2007) A Cheap And Easy Method For 3d C-Arm Reconstruction Using Elliptic Curves. Proc Spie 6509. Doi:Artn 65090b. Doi: 10.1117/12.712395    Dehghan E, Jain Ak, Moradi M, Wen X, Morris Wj, Salcudean Se, Gichtinger G (2011) Brachytherapy Seed Reconstruction With Joint-Encoded C-Arm Single-Axis Rotation And Motion Compensation. Medical Image Analysis 15 (5):760-771. Doi: 10.1016/J.Media.2011.05.017    U.S. Pat. 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No. 6,477,400B1: FLUOROSCOIC IMAGE GUIDED ORTHOPAEDIC SURGERY WITH INTRAOPERATIVE REGISTRATION    U.S. Pat. No. 6,491,429: METHOD OF AUTOMATIC GUIDING A C-ARM X-RAY DEVICE    U.S. Pat. No. 6,659,642: NON-CIRCULAR C-ARM FOR FLUOROSCOPIC IMAGING EQUIPMENT    U.S. Pat. No. 6,811,313: C-ARM X-RAY SYSTEM WITH ADJUSTABLE DETECTOR POSITIONING    U.S. Pat. No. 8,104,957: CALIBRATINGAC-ARM X-RAY APPARATUS    U.S. Pat. No. 8,374,678: MEDICAL APPARATUS WITH IMAGE ACQUISITION DEVICE AND POSITION DETERMINATION DEVICE COMBINED IN THE MEDICAL APPARATUS    US2001/0053204A1: METHOD AND APPARATUS FOR RELATIVE CALIBRATION OF A MOBILE X-RAY C-ARM AND AN EXTERNAL POSE TRACKING SYSTEM    US2003/0060703A1: FLUOROSCOPIC IMAGE GUIDED ORTHOPAEDIC SURGERY SYSTEM WITH INTRAOPERATIVE REGISTRATION    US2004/0171924A1: METHOD AND APPARATUS FOR PREPLANNING A SURGICAL PROCEDURE    US2011/0164721A1: X-RAY IMAGE RECORDING SYSTEM AND X-RAY RECORDING METHOD FOR RECORDING IMAGE DATA WITH X-RAY UNITS FOR VOLUME RECONSTRUCTION    US2011/0311030A1: C-ARM ROTATION ENCODING METHODS AND APPARATUS    US2012/0289821A1: C-ARM INTEGRATED ELECTROMAGNETIC TRACKING SYSTEM
There remains a need for practical and cost-effective ways to accurately track the positions of imaging devices such as C-arm x-ray fluoroscopy machines.